Seismic Stratigraphy and Sedimentology of the Post-Rift Lower Paleogene Sedimentary Succession in the Northern Norwegian North Sea: Implications for New Potential Stratigraphic Petroleum Plays

In the northern Norwegian North Sea, the Lower Paleogene post-rift succession constitutes an underexplored interval with considerable potential for stratigraphic petroleum plays. Nevertheless, predicting its subsurface prospectivity remains hindered by persistent uncertainties in facies architecture, depositional heterogeneity, and reservoir quality. To address these uncertainties, the present study integrates relative geologic time (RGT)-based seismic stratigraphic interpretation, spectral decomposition, sedimentary facies analysis, and litho-saturation assessment, primarily constrained by seismic and well-log datasets, to evaluate the Paleocene post-rift Lista Formation in the northern Norwegian North Sea. The results reveal the presence of Paleocene mass-transport deposit (MTD) complexes associated with axial lobe sandstones of submarine fan systems. These MTD complexes exhibit pronounced vertical and lateral facies transitions into low-density turbidites, debrites, and hemipelagic drapes, together forming an effective stratigraphic framework for hydrocarbon entrapment. Although the Lista submarine-fan sandstones are relatively thin, typically ranging from a few centimeters to decimeters in thickness, they display favorable reservoir characteristics. Litho-saturation analysis indicates preserved porosity and low water saturation (<20%), supporting their potential as effective hydrocarbon storage intervals. Distal fan-lobe sandstones, despite their limited thickness, show encouraging reservoir quality, whereas thicker low stand systems tract (LST) accumulations and time-equivalent carbonate mound complexes appear to have developed within more proximal structural domains. This proximal-to-distal facies organization reflects the dynamic interaction between tectonically inherited accommodation space and sediment-routing pathways during the early Paleocene. Overall, the findings highlight the significant petroleum prospectivity of the Paleocene post-rift succession in the northern Norwegian North Sea. The stratigraphic juxtaposition of sand-prone submarine-fan lobes against hemipelagic sealing intervals, combined with heterogeneity imposed by syn-rift structural inheritance, generates a highly favorable architecture for stratigraphic trapping. More broadly, the integrated workflow presented here enhances the predictive mapping of subtle stratigraphic traps within post-rift successions and provides a robust framework for reducing exploration uncertainty in analogous basins.